Replace old felt127 generation with constant (#317)

* Replace old felt127 generation with constant * Code refactor
NethermindEth · Mar 20, 2024 · 9ddf3a6 · 9ddf3a6
1 parent ce40eaf
commit 9ddf3a6
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Showing 3 changed files with 24 additions and 25 deletions.
diff --git a/pkg/hintrunner/zero/zerohint_uint256.go b/pkg/hintrunner/zero/zerohint_uint256.go
@@ -259,9 +259,8 @@ func newUint256SignedNNHint(a hinter.ResOperander) hinter.Hinter {
 				return err
 			}
 			var v memory.MemoryValue
-			felt127 := new(fp.Element).SetBigInt(new(big.Int).Lsh(big.NewInt(1), 127))
 
-			if utils.FeltLt(aHigh, felt127) {
+			if utils.FeltLt(aHigh, &utils.Felt127) {
 				v = memory.MemoryValueFromFieldElement(&utils.FeltOne)
 			} else {
 				v = memory.MemoryValueFromFieldElement(&utils.FeltZero)

diff --git a/pkg/hintrunner/zero/zerohint_uint256_test.go b/pkg/hintrunner/zero/zerohint_uint256_test.go
@@ -1,25 +1,21 @@
 package zero
 
 import (
-	"math/big"
 	"testing"
 
 	"github.com/NethermindEth/cairo-vm-go/pkg/hintrunner/hinter"
+	"github.com/NethermindEth/cairo-vm-go/pkg/utils"
 	"github.com/consensys/gnark-crypto/ecc/stark-curve/fp"
 )
 
 func TestZeroHintUint256(t *testing.T) {
-	// Values used in the test cases
-	// 1 << 127
-	felt127 := new(fp.Element).SetBigInt(new(big.Int).Lsh(big.NewInt(1), 127))
-
 	runHinterTests(t, map[string][]hintTestCase{
 		"Uint256Add": {
 			{
 				operanders: []*hintOperander{
-					{Name: "a.low", Kind: fpRelative, Value: felt127},
+					{Name: "a.low", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "a.high", Kind: fpRelative, Value: feltUint64(0)},
-					{Name: "b.low", Kind: apRelative, Value: felt127},
+					{Name: "b.low", Kind: apRelative, Value: &utils.Felt127},
 					{Name: "b.high", Kind: apRelative, Value: feltUint64(0)},
 					{Name: "carry_low", Kind: uninitialized},
 					{Name: "carry_high", Kind: uninitialized},
@@ -34,10 +30,10 @@ func TestZeroHintUint256(t *testing.T) {
 			},
 			{
 				operanders: []*hintOperander{
-					{Name: "a.low", Kind: fpRelative, Value: felt127},
-					{Name: "a.high", Kind: fpRelative, Value: felt127},
-					{Name: "b.low", Kind: apRelative, Value: felt127},
-					{Name: "b.high", Kind: apRelative, Value: felt127},
+					{Name: "a.low", Kind: fpRelative, Value: &utils.Felt127},
+					{Name: "a.high", Kind: fpRelative, Value: &utils.Felt127},
+					{Name: "b.low", Kind: apRelative, Value: &utils.Felt127},
+					{Name: "b.high", Kind: apRelative, Value: &utils.Felt127},
 					{Name: "carry_low", Kind: uninitialized},
 					{Name: "carry_high", Kind: uninitialized},
 				},
@@ -52,9 +48,9 @@ func TestZeroHintUint256(t *testing.T) {
 			{
 				operanders: []*hintOperander{
 					{Name: "a.low", Kind: fpRelative, Value: feltUint64(0)},
-					{Name: "a.high", Kind: fpRelative, Value: felt127},
+					{Name: "a.high", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "b.low", Kind: apRelative, Value: feltUint64(0)},
-					{Name: "b.high", Kind: apRelative, Value: felt127},
+					{Name: "b.high", Kind: apRelative, Value: &utils.Felt127},
 					{Name: "carry_low", Kind: uninitialized},
 					{Name: "carry_high", Kind: uninitialized},
 				},
@@ -68,10 +64,10 @@ func TestZeroHintUint256(t *testing.T) {
 			},
 			{
 				operanders: []*hintOperander{
-					{Name: "a.low", Kind: fpRelative, Value: felt127},
+					{Name: "a.low", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "a.high", Kind: fpRelative, Value: feltUint64(0)},
 					{Name: "b.low", Kind: apRelative, Value: feltUint64(0)},
-					{Name: "b.high", Kind: apRelative, Value: felt127},
+					{Name: "b.high", Kind: apRelative, Value: &utils.Felt127},
 					{Name: "carry_low", Kind: uninitialized},
 					{Name: "carry_high", Kind: uninitialized},
 				},
@@ -103,7 +99,7 @@ func TestZeroHintUint256(t *testing.T) {
 			// `low` is zero
 			{
 				operanders: []*hintOperander{
-					{Name: "a", Kind: fpRelative, Value: felt127},
+					{Name: "a", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "low", Kind: uninitialized},
 					{Name: "high", Kind: uninitialized},
 				},
@@ -179,8 +175,8 @@ func TestZeroHintUint256(t *testing.T) {
 			},
 			{
 				operanders: []*hintOperander{
-					{Name: "n.low", Kind: fpRelative, Value: felt127},
-					{Name: "n.high", Kind: fpRelative, Value: felt127},
+					{Name: "n.low", Kind: fpRelative, Value: &utils.Felt127},
+					{Name: "n.high", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "root.low", Kind: uninitialized},
 					{Name: "root.high", Kind: uninitialized},
 				},
@@ -197,7 +193,7 @@ func TestZeroHintUint256(t *testing.T) {
 			{
 				operanders: []*hintOperander{
 					{Name: "a.low", Kind: fpRelative, Value: feltUint64(0)},
-					{Name: "a.high", Kind: fpRelative, Value: felt127},
+					{Name: "a.high", Kind: fpRelative, Value: &utils.Felt127},
 				},
 				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
 					return newUint256SignedNNHint(ctx.operanders["a.low"])
@@ -239,9 +235,9 @@ func TestZeroHintUint256(t *testing.T) {
 			},
 			{
 				operanders: []*hintOperander{
-					{Name: "a.low", Kind: fpRelative, Value: felt127},
+					{Name: "a.low", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "a.high", Kind: fpRelative, Value: feltUint64(0)},
-					{Name: "div.low", Kind: fpRelative, Value: felt127},
+					{Name: "div.low", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "div.high", Kind: fpRelative, Value: feltUint64(0)},
 					{Name: "quotient.low", Kind: uninitialized},
 					{Name: "quotient.high", Kind: uninitialized},
@@ -261,9 +257,9 @@ func TestZeroHintUint256(t *testing.T) {
 			{
 				operanders: []*hintOperander{
 					{Name: "a.low", Kind: fpRelative, Value: feltUint64(5)},
-					{Name: "a.high", Kind: fpRelative, Value: felt127},
+					{Name: "a.high", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "div.low", Kind: fpRelative, Value: feltUint64(0)},
-					{Name: "div.high", Kind: fpRelative, Value: felt127},
+					{Name: "div.high", Kind: fpRelative, Value: &utils.Felt127},
 					{Name: "quotient.low", Kind: uninitialized},
 					{Name: "quotient.high", Kind: uninitialized},
 					{Name: "remainder.low", Kind: uninitialized},

diff --git a/pkg/utils/constant.go b/pkg/utils/constant.go
@@ -15,6 +15,10 @@ var FeltOne = fp.Element{
 	18446744073709551585, 18446744073709551615, 18446744073709551615, 576460752303422960,
 }
 
+// 1 << 127
+// same as 2 ** 127
+var Felt127 = fp.Element{18446744073704816641, 8703, 18446744073709551600, 576460752222928912}
+
 // 1 << 128
 // same as 2 ** 128
 var FeltMax128 = fp.Element{18446744073700081665, 17407, 18446744073709551584, 576460752142434320}